Angiotensin-Converting Enzyme C-Terminal Catalytic Domain Is the Main Site of Angiotensin I Cleavage In Vivo

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 51; no. 2; pp. 267 - 274
• Main Authors: Fuchs, Sebastien, Xiao, Hong D, Hubert, Christine, Michaud, Annie, Campbell, Duncan J, Adams, Jonathan W, Capecchi, Mario R, Corvol, Pierre, Bernstein, Kenneth E
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01-02-2008; Hagerstown, MD Lippincott
• Subjects: Angiotensin I - administration & dosage; Angiotensin I - metabolism; Angiotensin I - pharmacology; Angiotensin II - biosynthesis; Angiotensins - blood; Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - drug effects; Bradykinin - blood; Cardiology. Vascular system; Catalytic Domain - genetics; Endocrine kidney. Renin-angiotensin-aldosterone system; Fundamental and applied biological sciences. Psychology; Hematocrit; Infusions, Intravenous; Kidney - physiology; Medical sciences; Mice; Mice, Mutant Strains; Osmolar Concentration; Peptidyl-Dipeptidase A - genetics; Peptidyl-Dipeptidase A - metabolism; Point Mutation; Renin - blood; Substrate Specificity; Vertebrates: endocrinology; Zinc Fingers - genetics; Hypertension; Vasodilator agent; genetic mice model; Angiotensin I; Peptide hormone; Rodentia; Cardiovascular disease; catalytic sites; male infertility; Vertebrata; Mammalia; Mouse; Animal; Bradykinin; angiotensin; Arterial pressure; Blood pressure; angiotensin-converting enzyme
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.107.097865

Angiotensin-converting enzyme (ACE) plays a central role in the production of the vasoconstrictor angiotensin II. ACE is a single polypeptide, but it contains 2 homologous and independent catalytic domains, each of which binds zinc. To understand the in vivo role of these 2 domains, we used gene targeting to create mice with point mutations in the ACE C-domain zinc-binding motif. Such mice, termed ACE13/13, produce a full-length ACE protein with tissue expression identical to wild-type mice. Analysis of ACE13/13 mice showed that they produce ACE having only N-domain catalytic activity, as determined by the hydrolysis of domain specific substrates and by chloride sensitivity. ACE13/13 mice have blood pressure and blood angiotensin II levels similar to wild-type mice. However, plasma renin concentration is increased 2.6-fold and blood angiotensin I levels are increased 7.5-fold. Bradykinin peptide levels are not different from wild-type levels. ACE13/13 mice have a reduced increase of blood pressure after intravenous infusion of angiotensin I. ACE13/13 mice have a normal renal structure, but they are not able to concentrate urine after dehydration as effectively as wild-type mice. This study shows that the C-domain of ACE is the predominant site of angiotensin I cleavage in vivo. Although mice lacking C-domain activity have normal physiology under laboratory conditions, they respond less well to the stress of dehydration.